1. Field of the Invention
The present invention relates to an authentication device and authentication method for performing identity verification based on the imaged image of the person to be authenticated.
2. Description of the related art
The need for security strengthening is increasing with widespread use of portable terminals and strengthening of functions. In particular, ensuring of security is an absolute requirement when functions directly related to financial transactions such as electronic money are equipped.
In order to respond to such need, a living body authentication in which ensuring of security is easier is proposed in addition to security measures such as personal identification number and password of the prior art. Among them, face authentication is an identification method normally performed by people in ordinary living, and is often adopted since psychological resistance is small, it can be achieved with small investment since devices that can perform imaging are increasing with widespread use of CCD (Charge Coupled Device) camera etc.
However, similar to other authentication methods, a person other than the person in question (original person to be authenticated) pretends to be the person in question in face authentication. That is, in the conventional face authentication device, the image for authentication is acquired by imaging the person to be authenticated from the front, but the picture of the person in question taken from the front is relatively easy to obtain. Thus, a person can pass oneself to be the person in question by using the photo taken from the front.
FIG. 8 is a view explaining the method of carrying out spoofing using the photo of the person in question. As shown in FIG. 8, when carrying out spoofing using the photo of the person in question, the photo 52 with the face 53 of the person in question is arranged in front of the camera 51 of the portable telephone 50 and the photo 52 is imaged. Spoofing is carried out by performing such imaging and disguising as if imaging the face of the person in question.
In order to solve such problem, a device for preventing mistaken authentication due to spoofing by using the image imaged from a direction other than from the front in face authentication has been developed.
For example, in a personal authentication device disclosed in Japanese Laid-Open Patent Publication No. 2003-178306 (published Jun. 27, 2003), the face of the person to be authenticated is imaged from a specific direction defined in advance other than from the front, and the imaged image is registered in an authentication dictionary. In time of authentication, determination is made on whether or not the person to be authenticated is the person in question by checking the face image of the face to be authenticated imaged from the specific direction and the image registered in the authentication dictionary.
Although it is not the device for identity verification, the invention for performing human authentication by imaging the image of a human from below includes an image processing device disclosed in Japanese Laid-Open Patent Publication No. 2000-259814 (published Sep. 22, 2000). In such image processing device, an image input unit for imaging the image of the human from diagonally below is arranged, and human authentication is performed based on the image acquired by the image input unit. The face image of the target person can be reliably obtained even if the height of the target person varies by imaging from diagonally below.
An invention of a method for extracting feature points of the face from the image for face authentication includes a feature point extracting method disclosed in Japanese Laid-Open Patent Publication No. 9-251534 (published Sep. 22, 1997).